package org.eclipse.jetty.security;
   
   import java.io.File;
   import java.io.FilenameFilter;
   import java.io.IOException;
   import java.util.ArrayList;
   import java.util.HashSet;
   import java.util.Iterator;
   import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  import java.util.Set;
  
  import org.eclipse.jetty.http.security.Credential;
  import org.eclipse.jetty.util.Scanner;
  import org.eclipse.jetty.util.Scanner.BulkListener;
  import org.eclipse.jetty.util.component.AbstractLifeCycle;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.util.resource.Resource;
  
  /**
   * PropertyUserStore
   * 
   * This class monitors a property file of the format mentioned below and notifies registered listeners of the changes to the the given file.
   * 
   * <PRE>
   *  username: password [,rolename ...]
   * </PRE>
   * 
   * Passwords may be clear text, obfuscated or checksummed. The class com.eclipse.Util.Password should be used to generate obfuscated passwords or password
   * checksums.
   * 
   * If DIGEST Authentication is used, the password must be in a recoverable format, either plain text or OBF:.
   */
  public class PropertyUserStore extends AbstractLifeCycle
  {
      private static final Logger LOG = Log.getLogger(PropertyUserStore.class);
  
      private String _config;
      private Resource _configResource;
      private Scanner _scanner;
      private int _refreshInterval = 0;// default is not to reload
  
      private boolean _firstLoad = true; // true if first load, false from that point on
      private final List<String> _knownUsers = new ArrayList<String>();
      private List<UserListener> _listeners;
  
      /* ------------------------------------------------------------ */
      public String getConfig()
      {
          return _config;
      }
  
      /* ------------------------------------------------------------ */
      public void setConfig(String config)
      {
          _config = config;
      }
  
      /* ------------------------------------------------------------ */
      /**
       * returns the resource associated with the configured properties file, creating it if necessary
       */
      public Resource getConfigResource() throws IOException
      {
          if (_configResource == null)
          {
              _configResource = Resource.newResource(_config);
          }
  
          return _configResource;
      }
  
      /* ------------------------------------------------------------ */
      /**
       * sets the refresh interval (in seconds)
       */
      public void setRefreshInterval(int msec)
      {
          _refreshInterval = msec;
      }
  
      /* ------------------------------------------------------------ */
      /**
       * refresh interval in seconds for how often the properties file should be checked for changes
       */
      public int getRefreshInterval()
      {
          return _refreshInterval;
      }
  
      /* ------------------------------------------------------------ */
      private void loadUsers() throws IOException
      {
          if (_config == null)
              return;
  
          if (LOG.isDebugEnabled())
             LOG.debug("Load " + this + " from " + _config);
         Properties properties = new Properties();
         if (getConfigResource().exists())
             properties.load(getConfigResource().getInputStream());
         Set<String> known = new HashSet<String>();
 
         for (Map.Entry<Object, Object> entry : properties.entrySet())
         {
             String username = ((String)entry.getKey()).trim();
             String credentials = ((String)entry.getValue()).trim();
             String roles = null;
             int c = credentials.indexOf(',');
             if (c > 0)
             {
                 roles = credentials.substring(c + 1).trim();
                 credentials = credentials.substring(0,c).trim();
             }
 
             if (username != null && username.length() > 0 && credentials != null && credentials.length() > 0)
             {
                 String[] roleArray = IdentityService.NO_ROLES;
                 if (roles != null && roles.length() > 0)
                     roleArray = roles.split(",");
                 known.add(username);
                 notifyUpdate(username,Credential.getCredential(credentials),roleArray);
             }
         }
 
         synchronized (_knownUsers)
         {
             /*
              * if its not the initial load then we want to process removed users
              */
             if (!_firstLoad)
             {
                 Iterator<String> users = _knownUsers.iterator();
                 while (users.hasNext())
                 {
                     String user = users.next();
                     if (!known.contains(user))
                     {
                         notifyRemove(user);
                     }
                 }
             }
 
             /*
              * reset the tracked _users list to the known users we just processed
              */
 
             _knownUsers.clear();
             _knownUsers.addAll(known);
 
         }
 
         /*
          * set initial load to false as there should be no more initial loads
          */
         _firstLoad = false;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Depending on the value of the refresh interval, this method will either start up a scanner thread that will monitor the properties file for changes after
      * it has initially loaded it. Otherwise the users will be loaded and there will be no active monitoring thread so changes will not be detected.
      * 
      * 
      * @see org.eclipse.jetty.util.component.AbstractLifeCycle#doStart()
      */
     protected void doStart() throws Exception
     {
         super.doStart();
 
         if (getRefreshInterval() > 0)
         {
             _scanner = new Scanner();
             _scanner.setScanInterval(getRefreshInterval());
             List<File> dirList = new ArrayList<File>(1);
             dirList.add(getConfigResource().getFile().getParentFile());
             _scanner.setScanDirs(dirList);
             _scanner.setFilenameFilter(new FilenameFilter()
             {
                 public boolean accept(File dir, String name)
                 {
                     File f = new File(dir,name);
                     try
                     {
                         if (f.compareTo(getConfigResource().getFile()) == 0)
                         {
                             return true;
                         }
                     }
                     catch (IOException e)
                     {
                         return false;
                     }
 
                     return false;
                 }
 
             });
 
             _scanner.addListener(new BulkListener()
             {
                 public void filesChanged(List filenames) throws Exception
                 {
                     if (filenames == null)
                         return;
                     if (filenames.isEmpty())
                         return;
                     if (filenames.size() == 1 && filenames.get(0).equals(getConfigResource().getFile().getAbsolutePath()))
                     {
                         loadUsers();
                     }
                 }
 
                 public String toString()
                 {
                     return "PropertyUserStore$Scanner";
                 }
 
             });
 
             _scanner.setReportExistingFilesOnStartup(true);
             _scanner.setRecursive(false);
             _scanner.start();
         }
         else
         {
             loadUsers();
         }
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @see org.eclipse.jetty.util.component.AbstractLifeCycle#doStop()
      */
     protected void doStop() throws Exception
     {
         super.doStop();
         if (_scanner != null)
             _scanner.stop();
         _scanner = null;
     }
 
     /**
      * Notifies the registered listeners of potential updates to a user
      * 
      * @param username
      * @param credential
      * @param roleArray
      */
     private void notifyUpdate(String username, Credential credential, String[] roleArray)
     {
         if (_listeners != null)
         {
             for (Iterator<UserListener> i = _listeners.iterator(); i.hasNext();)
             {
                 i.next().update(username,credential,roleArray);
             }
         }
     }
 
     /**
      * notifies the registered listeners that a user has been removed.
      * 
      * @param username
      */
     private void notifyRemove(String username)
     {
         if (_listeners != null)
         {
             for (Iterator<UserListener> i = _listeners.iterator(); i.hasNext();)
             {
                 i.next().remove(username);
             }
         }
     }
 
     /**
      * registers a listener to be notified of the contents of the property file
      */
     public void registerUserListener(UserListener listener)
     {
         if (_listeners == null)
         {
             _listeners = new ArrayList<UserListener>();
         }
         _listeners.add(listener);
     }
 
     /**
      * UserListener
      */
     public interface UserListener
     {
         public void update(String username, Credential credential, String[] roleArray);
 
         public void remove(String username);
     }
 }